Benzothiazolium compounds for controlling overdevelopment



United States Patent OflFice 3,342,596 Patented Sept. 19, 1967 This invention relates to color photography, and more particularly to a method of processing multilayer color films or papers at elevated temperatures.

In multilayer photographic elements used for color photography, there are usually three selectively sensitive emulsion layers coated on one side of a single support. For example, the uppermost layer is generally blue sensitive, the next layer is generally green sensitive, while the emulsion layer adjacent the support is generally red sensitive. Between the blue sensitive and green sensitive layers is a filter layer for absorbing blue radiation which may be intermitted through the blue sensitive layer. In some multilayer photographic elements there are dye forming couplers which react with the oxidation products of the silver halide developer to form dyes. The multilayer coating can also have other interlayers for specialized purposes. Such multilayer materials have been previously described in the prior art, such as US. Patents 2,322,027, issued June 15, 1943, and 2,644,900, issued July 12, 1960. Other arrangements of the sensitive layers are also shown.

Processing of multilayer photographic elements used for color photography is generally a time-consuming process so that it has been desirable to find a more rapid method of obtaining the processed film, particularly those containing incorporated dye forming couplers. Accordingly, since it is well known that increasing the temperature of a photographic developer will increase the rate at which it develops a silver halide emulsion, it has been proposed to process the multilayer photographic emulsions in a rapid, high temperature color process.

Normally a necessary step in preventing over-development of an emulsion when processed at a higher temperature is to shorten the time of development to an appropriate level. However, shortening the time of development of a color material will not, by itself, given balanced development in the separated layers of a normal color material. If the development time is adjusted for color development of the top, blue sensitive layer, then the lower green and red sensitive layers will be underdeveloped. It the time is adjusted so that the lower layers are correctly developed, then the top layer will be greatly overdeveloped. Moreover, adjustments in the speeds of emulsion will not balance the amount of development in a multilayer system. Therefore, the rate of development of each emulsion must be controlled so that all layers will arrive at optimum development at a given time.

I have found that the overdevelopment of the top emulsion layer can be controlled during high temperature processing by the addition of a benzothiazolium salt to the top emulsion layer.

One object of this invention is to provide a multilayer photographic element having the rate of development controlled in the top emulsion layer so that it can he satisfactorily processed in a rapid, high temperature color process. A further object is to provide a prebath, such as a prehardener bath, in which a benzothiazolium salt is imbibed into the top layer of a multilayer photographic element to control its rate of development. Other objects will be apparent from the following disclosure.

The overdevelopment of the top emulsion layer in a multilayer color coating can be controlled by the addition of a benzothiazoliurn salt to the top emulsion layer. About 1-10 grams of the compound per silver mole are required for this purpose. These compounds may be incorporated in the emulsion, by incorporating the salt in a layer over the top light sensitive layer, or they may be added in a bath, such as a prehardener bath, prior to development. We prefer to use the following compounds. For example:

However, other useful salts are represented by the following general formula:

.O o R BIT-X 2) wherein R represents a hydrogen atom or a lower alkyl group, such as methyl, ethyl, etc. (e.g. an alkyl group containing from 1-2 carbon atoms), R represents a hydrogen atom, an aryl group (e.g. phenyl, o-, mor ptolyl, 0-, mor p-methoxyphenyl, etc.) or an arylenethiazolyl group (e.g. 2-benzothiazolyl, 3-benzothiazolyl, 2-(B-naphthothiazolyl) etc.), D represents the non-metallic atoms necessary to complete an aromatic nucleus (e.g. benzene, naphthalene, etc., as well as their substitution products, including such members substituted by methyl, ethyl, methoxyl, ethoxyl, etc.), it represents a positive integer of from 1-26 (provided that n represents a positive integer of only from about 1-3 when R represents an aryl group) and X represents an acid radical such as perchlorate, bromide, benzenesulfonate, toluenesulfonate, methyl sulfate, ethyl sulfate, etc.

A particularly useful group of quaternary salts embraced by Formula A above includes the compounds represented by the following general formula:

wherein R, D and X each have the values given above, and m represents a positive integer of from about l-26.

Typical quaternary salts embraced by Formula A above include, for example, the following:

Decamethylene-bis-benzothiazolium perchlorate 3-ethylbenzothiazolium-p-toluenesulfonate (I1) H; OSOz-CaHr-CHa (p) 3-hexylbenz0thiazolium-p-toluenesulfonate 3- (2-benzothiazo1ylmethyl) -b enzothiazolium-ptoluenesulfonate 3-nonylbenzothiazolium-p-toluenesulfonate B B r Trimethylene-bis-2-methylbenzothiazolium bromide C-CH;

Decainethylene-bis-(Z-methylbenzothiazolium)- perchlorate S U C-CH3 s S O: O EHF 0 I N C-CH:

2-methyl-]3-naphthothiazolium metho-p-toluenesulfonate s s m. .w

IIq OHQCHW Br Br Ethylene-bis-benzothiazoliurn bromide CH HC X C104 C104 H exarnethylene b is-b enzothiazolium p erchlo rate S\CH Cl CH2CsH5 3-benzylbenzothiazolium chloride Heptamethylene-bis-benzothiazolium perchlorate 0104 010i Nonamethylene-bis-benzothiazolium perchlorate N -(CH2)2o-N 104 010, Hexacosane-1,26-bis-benzothiazolium perchlorate Many of these quaternary compounds have been previously described in the prior art. For example, the his com pounds represented by Formula B can be prepared according to the methods described in Wilson US. (Patent 2,425,774, issued Aug. 19, 1947, as well as by the method described by Allen and Wilson US. Patent 2,694,716, issued Nov. 16, 1954. Such methods generally comprise the fusion of a heterocyclic base with an alkylene halide. Such techniques are well known to those skilled in the art. Alkyl esters of organic sulfonic acids can also be fused with thiazole bases to provide the salts of my invention.

When the cycloammonium salts useful in practicing my invention are employed in a prebath, they are used in the form of their aqueous solutions, and if desired, the prebath may contain known hardeners such as form-aldehyde, succinaldehyde, mucochloric acid, chrome alum, etc. The amount of qua-ternary salt used in the solutions can be varied, depending upon the particular emulsions employed, the concentration of silver halide in the emulsions, etc.

When incorporated in the emulsion or in an overcoat, the cycloammonium salts may be incorporated as aqueous solutions, alcohol-water solutions, or by any other manner known in the art.

The following examples are intended to illustrate my invention but not to limit it in any way.

EXAMPLE 1 Four photographic films were made consisting of a cellulose acetate support coated with a blue sensitive silver bromoiodide gelatin emulsion containing a keto-methylene yellow color former such as coupler No. XIV of US. Patent 2,875,057. These coatings were alike except for the following changes.

Coating: Feature A Control, no further change. B Like control except compound I added at 6.0 g./Ag mole. C Like control except compound III added at 2.0 g./Ag mole. D Like control except compound IV added at 2.0 g./Ag mole.

160 F. Compound Used ADM! Control Reference. I +.46.

III... 30 IV 23 EXAMPLE 2 Three photographic films were made consisting of a cel- The figures obtained here show a direct relationship between the control of the rate of development and the temperature at which the development can be carried out Thus, by control of the rate of development, the temperature of the process may be elevated, giving a rapid process with times of development within practical limits.

The transition to a multilayer color film can be shown by the following example.

EXAMPLE 3 Two multilayer films were made consisting of a cellulose acetate support coated with a red sensitive silver bromoiodide gelatin emulsion containing a phenolic cyan color former over which was coated a gelatin interlayer. Next, a green sensitive silver bromoiodide emulsion layer was coated containing a pyrazolone magenta color former and over this a yellow filter layer. Over the entire film a blue sensitive silver bromoiodide emulsion was then coated containing a keto-methylene yellow color former and finally a gelatin overcoat.

The films were alike except for the following changes.

Coating: Feature H No further change. I Like H except compound IV added to the blue sensitive layer only at 4.85 g./Ag mole.

Each coating was given a sensitometric exposure and processed to a color positive in the reversal process of Example 1 at 75 F. and 160 F. The time of development in the negative developer of the high temperature process was adjusted so that the film with the controlled rate of development would approximate the speed of the lulose acetate support coated with a blue sensitive silver control film in the standard temperature process.

Red Green Blue Process Coating Temp., F. Du. Relative Dmu Relative Dm Relative Speed Speed Speed 2.87 100 a. 29 100 2.08 I 75 3.14 100 a. 74 91 4. 00 23 160 3.08 100 3.7 100 3.76 100 1 Not measurable; over-developed.

bromoiodide gelatin emulsion containing a keto-methylene yellow color former as described in Example 1. These coatings were alike except for the following changes.

Coating: Feature E. Control, no further change. F Like control except compound II added at 3 g./Ag mole. G Like control except compound II added at 6 g./Ag mole.

Each coating was given in a sensitometric exposure and processed to a color positive in the process of Example I at 75 F. and at 160 F. The change in the rate of development is shown here by the Dmaxes, and the relative emulsion speeds at the extreme development temperatures.

The results here show that the control of rate of development can be introduced into a multilayer color coating, this control is applicable at high processing temperatures and that this control can be confined to a particular layer of a multilayer film as desired.

The rate of development control shown above 'by these compounds is also applicable to films given direct negative color development such as in a para-phenylenediamine-type process.

EXAMPLE 4 A negative multilayer coating I was prepared consisting of a celulose acetate support coated with a red sensitive layer silver bromoiodide gelatin emulsion containing a phenolic cyan color former and 0.05 g./Ag mole of com- 1 N 0t measurable.

pound I over which was coated a gel interlayer. Next, a green-sensitive silver bromoiodide emulsion layer was coated containing a pyrazolone magenta color former and 0.225 g./Ag mole of compound I and over this a yellow filter layer. Over the entire film a blue-sensitive silver bromoiodide emulsion was coated containing a ketomethylene yellow color former and 2.25 g./Ag mole of compound I.

This coating J was compared with a product coating K of similar structure but containing no compound I. Each coating was given a sensitometric exposure and processed to a color negative in a negative process referred to below in the article by Hanson et al. The following results were obtained.

The prehardener bath was prepared as follows: 800 ml. of water at 90 F. was used to dissolve 4.30 ml. of dimethoxytetrahydrofuran, 5.41 ml. of 18 Normal sulfuric acid and 0.5 gram of the sodium salt of para-toluenesulfinic acid. This solution was stirred for 10 minutes at 90 F. whereby the DMTF became hydrolyzed to succinaldehyde. 133 grams of sodium sulfate and 2 grams of sodium bromide were then added and the composition was mixed for 20 minutes. There was then added 20 grams of sodium acetate and 27 ml. of formalin, the volume was then brought to one liter with water and the pH was adjusted to 4.8 at 80 F.

Incorporation of the same amount of N-methyl-benzothiazolium-p-toluene sulfonate in the negative developer A typical negative color process as referred to is described in detail by W. T. Hanson, In, and W. I. Kisner in an article in the Journal of the Society of Motion Picture and Television Engineers, vol. 61 (1953), pp. 66770l, incorporated herein by reference.

EXAMPLE 5 Twelve photographic films were made consisting of a cellulose acetate support coated with a blue-sensitive silver bromoiodide gelatin emulsion containing a ketomethylene yellow color former. These coatings were alike except for the features as listed.

Each coating was given a sensitometric exposure and processed to a color positive in the process of Example 1 either at 75 F. or at 160 F. The change in the rate of development of the emusions with each of the addenda present is shown by the dye D Feature 75 F. 160 F.

Dam Dram:

Control 2. 24 1. 18 Compound I at 0.1 g./Ag mole 0.99 Compound I at 0.5 gJAg mo1e 1. 09 Compound II at 0.1 g./Ag mo e. 1. 04 Compound II at 0.5 g./Ag mo 1. 24 Compound V 1 at 0.1 g./Ag mole 1. 29 Compound V 2 at 0.5 g./Ag mole 1. 52 Control 1. 40 Compound III at 0.1 gJAg mol 1. 08 Compound III at 0.5 g. 1. 31 Compound IV at 0.1 gJAg mole 1. 00 Compound IV at 0.5 gJAg mole 1.22

1 Compound V is 1-phenyl-S-mercaptotetrazole.

2 Compound V at 0.5 g./Ag mole also shows a speed loss of approximately 1.10 log E compared to the control.

These results show that when the compounds are used in an antifoggant amount such as 2-8 mg. per 100 cc. of photographic emulsion, that they are incfiective in reducing the rate of development at elevated temperatures. Two to eight mg. per 100 cc. of emulsion corresponds to about 300 mg./Ag mole. The use of a conventional antifoggant, compound V, is also ineffective, since it results in a speed loss.

EXAMPLE 6 A multilayer film of Example 3, identified as H, was immersed in a prehardener bath containing 20 milligrams per liter of N-methyl benzothiazolium-p-toluene sulfonate for 2 /2 minutes. It was then passed through a neutralizer bath and processed as in Example 3 with similar results to those obtained with coating I, in which the compound was incorporated in the emulsion.

at 160 F. had no appreciable efi'ect in restraining the development. Overdevelopment occurred in the top layer.

When used in a bath prior to development, from 1-200 milligrams per liter of the bath are employed. This may be a bath containing water and the benzothiazolium salt or the benzothiazolium salt may be used in a prehardener bath containing hardening agents which aid in conditioning the photographic element so that it can be processed at relatively high temperatures. The prehardener bath may be at any suitable temperature from 50 F. to 200 F., since the purpose of the bath is to imbibe the benzothiazolium salt into the top layer of the multilayer element. The developer is preferably above 100 F., but is useful range is from F. to 200 F.

The amount of benzothiazolium salt, whether incorporated in the bath or in the silver halide emulsion, depends upon the temperature at which the development is carried out within the ranges given above. This can be accomplished in the bath 'by increasing the concentration of the benzothiazolium salt or by leaving the photographic element in the bath for a longer period of time, or a combination of the two. In a preferred embodiment, the multilayer element is immersed in the bath for 2% minutes, the bath contains hardeners and the temperature is close to that of the developer solution.

It will be appreciated that supports customarily used in the art may be used for the silver halide emulsion as well as customary light sensitive silver halide salts and colloid vehicles such as gelatin and the like which can be hardened chemically.

Various color emulsions may be used and these emul- SIOIIS may comprise various layer arrangements. For instance, the support may carry thereon a blue-sensitive layer containing a yellow coupler, an interlayer, a greensensitive layer containing cyan and magenta couplers and having thereon an overcoat. These couplers may occur in different layers and in different orders as a matter of choice. It will be appreciated that various supports known in the art may be used for the silver halide emulsion and that if a transparent support is used, that one or more light-sensitive layers may be coated on one side and one or more layers on the other side, provided the benzothiazolium salt is used on both sides of the support. Another useful photographic element may have a bleachable filter layer incorporated in the element between two light-sensitive layers or on the support when it is between the lightsensitive layers. In still another useful element, the lightsensitive elements can have one or more strata of the type described in Millikan U.S. Ser. No. 159,057, filed Dec.

1-phenyl-3-chloroacetylarnino-5-pyrazolone 1-phenyl-3 -dichloroacetylamino-5 -pyrazolone 1-phenyl-3 -b enzoylarnino-S -pyrazolone 1-phenyl-3- (m-amino'b enzoyl) amino-5 -pyrazolone 1-phenyl-3-(p-sec. amylbenzoylamino -5-pyrazolone 1-phenyl-3 -diarnylbenzoylamino-5-pyrazolone 1-phenyl-3-,8-naphthoylarnino-5 -pyrazolne 1-phenyl-3 -phenylcarbamylamino- -pyrazolor1e 1-phenyl-3 -palmitylamino-5 -pyrazol one 1-phenyl-3 -benzenesulfonylamino-5 -pyrazolone l-(p-phenoxyphenyl) -3- (p-tert. amyloxybenzoyl) amino- S-pyrazolone 1-(2,4,6-tribromophenyl) -3 -benzamido-5-pyrazolone 1-(2',4,6-trichloropheny1) -3-benzamido-5-pyrazolone 1-( 2',4',6'-trichlorophenyl) -3 -phenylacetamido-5-pyrazolone 1- (2,4,6'-tribromophenyl -3-phenylacetamido-5-pyrazolone 1- (24'-dich1orophenyl) -3- [3"- (2",4"'-di-tert. amylphenoxyacetamido benzamido] -5-pyrazolone 1- (2',4,6'-trich1orophenyl) -3- [3 (2",4"'-di-tert.

amylphenoxyacetamido benzamido] -5 -pyrazolone 1- (2',4',6-tribromophenyl -3- [3 2"',4"'-di-tert. amylphenoxyacetamido)benzamido] -5-pyrazolone 1- (2,4',6'-trichlorophenyl -3- (2',4'-di-tert. amylphenoxy propionamido] -5-pyrazolone 1- (2,4',6-tribromophenyl) -3- ,6- (2",4"'-di-tert. amylphenoxy) propiona-mido] -5-pyrazolone 1- (2,5 -dich1oro -3- 3"- (4'-tert. amylphenoxy) benzamido] -5 -pyrazo1one 1- 2',4',6'-tribrornophenyl)-3 [3 "-(4-tert. amylphenoxy) -benzarr 1ido] -5 -pyrazolone 1-(2,5'-dichlorophenyl) -3- [3 (2',4'-di-tert. amylphenoxyaeetamido benzamido] -5-pyrazolone 1- (2,4',6-trichlorophenyl) 3- (4-nitroanilino) -5- pyrazolone Couplers producing yellow images N-amyl-p-b enzoylacetaminobenzenesulfonate N- (4-anisoylacetaminob enzenesulfonyl) -N-benzyl-mtoluidine N- (4-benzoylacetaminobenzenesulfonyl) -N-benzy1-mtoluidine N- (4-benzoylacetaminobenzenesulfonyl) -N-n-amyl-ptoluidine N- (4 b enzoyl acetaminob enzenesulfonyl) -N-b enzyl aniline w- (p-B enzoylbenzoyl) acetanilide w-Benzoylacet-2,S-dichloroanilide w-B enzoyl-p-sec. amylacetanilide N,N'-di (w-benzoylacetyl) -p-phenylenediamine N,N-diacetoacetarnino diphenyl oc-{3- [a-(2,4-di-tert.-amylphenoxy )butyramido] benzoyl}- 2-methoxyacetanilide oc-{3- (2,4-di-tert.-amylphenoxy) acetamido]benzoyl}- 2-methoxyacetanilide 4,4'-di-( acetoacetamino) -3 ,3 -dimethyldiphenyl p,p'-diaceto acetamino diphenylmethane Ethyl-p-b enzoylacetaminobenzenesulfonate Nonyl-p-b enzoylacetaminobenzenesulfonate N-phenyl-N- (p-acetoacetarninophenyl urea n-Propyl-p-benzoylacetaminobenzenesulfonate acetoacetpiperidine w-B enzoylacetpiperidide N(w-benzoylacetyl)-1,2,3 ,4-tetrahydroquinoline N w-benzoylacetyl morpholine In the silver halide emulsions in the color element, various silver salts may be used as the sensitive salts, including silver bromide, silver iodide, silver chloride or silver halide such as silver chlorobromide, silver bromoiodide, etc.

The emulsions can be chemically sensitized by any of the accepted procedures. The emulsions can be digested 12 with naturally active gelatin, or sulfur compounds can be added such as those described in Sheppard U.S. Patent 1,574,944, issued Mar. 2, 1926; Sheppard et al. U.S. Patent 1,623,499, issued Apr. 5, 1927; and Sheppard et a1. U.S. Patent 2,410,689, issued Nov. 5, 1946.

The emulsions can also be chemically sensitized with reducing agents such as stannous salts (Carroll U.S. Patent 2,487,850, issued Nov. 15, 1949), polyarnines, such as diethyl triamine (Lowe and Jones U.S. Patent 2,518,- 698, issued Aug 15, 1950), polyamines, such as spermine (Lowe and Allen U.S. Patent 2,521,925, issued Sept. 12, 1950), or bis(fl aminoethyl)sulfide and its water-soluble salts (Lowe and Jones U.S. Patent 2,521,926, issued Sept. 12, 1950).

In preparation of the silver halide dispersions employed for preparing silver halide emulsions, there may be employed as the carrier for the silver halide in its preparation, gelatin or some other colloidal material such as colloidal albumin, a cellulose derivative, or a synthetic resin, for instance, a polyvinyl compound. Some colloids which may be used are polyvinyl alcohol or a hydrolyzed polyvinyl acetate as described in Lowe U.S. Patent 2,286,- 215, issued June 16, 1942; a far hydrolyzed cellulose ester such as cellulose acetate hydrolyzed to an acetyl content of 1926% as described in U.S. Patent 2,326,808 of Lowe and Clark, issued Aug. 24, 1943; a water-soluble ethanolamine cellulose acetate as described in Yutzy U.S. Patent 2,322,085, issued June 15, 1943; a polyacrylamine having a combined aerylamide content of 3060% and a specific viscosity of 025-15 on an imidized polyacrylamide of like acrylamide content and viscosity as described in Lowe, Minsk and Kenyon U.S. Patent 2,541,- 474, issued Feb. 13, 1951; zein as described in Lowe U.S. Patent 2,563,791, issued Aug. 7, 1951; a vinyl alcohol polymer containing urethane carboxylic acid groups of the type described in Unruh and Smith U.S. Patent 2,768,- 154, issued Oct. 23, 1956; or containing cyano-acetyl groups such as the vinyl alcohol-vinyl cyanoacetate copolymer as described in Unruh, Smith and Priest U.S. Patent 2,808,331, issued Oct. 1, 1957; or a polymeric material which results from polymerizing a protein or a saturated acylated protein with a monomer having a vinyl group as described in U.S. Patent 2,852,382, of Illingsworth, Dann and Gates, issued Sept. 16, 1958.

Included among the green sensitizers are acid merocyanines of Brooker et al. U.S. Patent 2,493,747, issued Jan. 10, 1950, such as 3 (p-carboxypheny1) -5( 3-methy1-2( 3 -benzoxazolylidene -rhodanine,

l-(p-carboxyphenyl) -4- 3-ethyl-2 (3 -benzothiazo1ylideneisopropylidene] -3-methyl-5-pyrazolone,

3 ethyl-S- 3-ethyl-2( 3 -benzoxazolylidene ethylidene] 2 [3-methyl-5-oxo-1-(p-sulfophenyl) -4-(2-pyrazolinylidene) 1-4-thiazolidone, etc.;

the merocycanines of Brooker et al. U.S. Patent 2,493,- 748, issued J an. 10, 1950, such as cyanines of Brooker et al. U.S. 2,493,747, issued Jan. 10, 1950, such as 1 3 4 ['(5 ch-loro-3-ethyl-2(3)-benzothiazolylidene)alt-ethylethylidene] 3-methyl-1-(p-sulfophenyl)-5-pyrazolone, etc.

the merocyanines of Brooker et al. US. such as 3 carboxymethyl 5-(3-ethyl-2(3)-benzothiazolylidene)- rhodanine, etc.; and other sensitizers well known in the art.

The invention has been described in detail with particular reference to preferred embodiments thereof, but it Will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

Patent 2,493,7 48,

" 1. A multilayer photographic element comprising a wherein R represents a member selected from the class consisting of a hydrogen atom and a lower alkyl group, R represents a member selected from the class consisting of a hydrogen atom, an aryl group and an arylenethiazolyl group, D represents the non-metallic atoms necessary to complete an aromatic nucleus, X represents an acid radical and n represents a positive integer of from 1 to 26 when R represents a member selected from the class consisting of a hydrogen atom and an arylenethiazolyl group, and n represents a positive integer of from 1 to 3 when R represents an aryl group.

2. The photographic element of claim 1 wherein said compound is benzothiazole-methiodide.

3. The photographic element of claim 1 wherein said compound is decamethylene-bis-benzothiazolium perchlorate.

4. The photographic element of claim 1 wherein said compound is propane-1,3-bis-(3-methyl-2-benzothiazolium-p-toluene sulfonate).

5. The photographic element of claim 1 wherein said compound is pentane-1,5-bis*(3-methyl-2-benzothiazolium-p-toluene sulfonate).

6. A prehardener bath for treating a photographic element having at least one gelatino-silver halide emulsion layer comprising:

(a) a hardening concentration of a gelatin hardening agent, and

(b) an aqueous solution containing from about 1-200 milligrams per liter of a compound having the following general formula:

wherein R represents a member selected from the class consisting of a hydrogen atom and a lower alkyl :group, R represents a member selected from the class consisting of a hydrogen atom, an aryl group and an arylenethiazolyl group, D represents the non-metallic atoms necessary to complete an aromatic nucleus, X represents an acid radical and n represents a positive integer of from 1 to 26 when R represents a member selected from the class consisting of a hydrogen atom and an arylenethiazolyl group, and n represents a positive integer of from 1 to 3 when R represents an aryl group.

7. The prehardener bath of claim 6 wherein said compound is N-methyl-benzothiazolium-p-toluene sulfonate.

8. The prehardener bath of claim 6 wherein said compound is decamethylene-bis-benzothiazolium perchlorate.

9. The prehardener bath of claim 6 wherein said compound is propane-ll,3 bis-(3-methyl-2-benzothiazolium-ptoluene sulfonate).

10. The prehardener bath of claim 6 wherein said compound is pentane-l,5-bis-(3-methyl-2-benzothiazolium-ptoluene sulfonate).

11. A hardening composition for use in an aqueous prehardener bath for treating a photographic element having at least one gelatino-silver halide emulsion layer comprising a gelatin hardening agent and a compound for preventing overdevelopment of the top emulsion layer and having the following general formula:

/S i R 0 six 2));

wherein R represents a member selected. from the class consisting of a hydrogen atom and a lower alkyl group, R represents a member selected from the class consisting of a hydrogen atom, an aryl group and an arylenethiazolyl group, D represents the non-metallic atoms necessary to complete an aromatic nucleus, X represents an acid radical and n represents a positive integer of from 1 to 26 when R represents a member selected from the class consisting of a hydrogen atom and an arylene'thiazolyl group, and n represents a positive integer of from 1 to 3 when R represents an aryl group.

12. The composition of claim 11 wherein said compound is N-methy-l-benzothiazolium-p-toluene sulfonate.

13. The composition of claim 11 wherein said compound is decamethylene-bis-benzothiazolium perchlorate.

14. The composition of claim 11 wherein said comound is propane-l,3-bis (3-methyl-2-benzothiaZolium-ptoluene sulfonate).

15. The composition of claim 11 wherein said compound is pentane-l,5-bis-(3-methyl-Z-benzothiazolium-ptoluene sulfonate).

16. In a process for developing exposed multilayer silver halide photographic elements, the step of imbibing into the top silver halide layer before development, about 1 to about 10 grams per silver mole in said top silver halide layer of a compound having the following general wherein R represents a member selected from the class consisting of a hydrogen atom and a lower alkyl group,

R represents a member selected from the class consisting of a hydrogen atom, an aryl group and an arylenethiazolyl group, D represents the non-metallic atoms necessary to complete an aromatic nucleus, X represents an acid radical and n represents a positive integer of from 1 to 26 when R represents a member selected from the class consisting of a hydrogen atom and an arylenethiazolyl group, and n represents -a positive integer of from 1 to 3 when R represents an aryl group.

17. The process of claim 16 wherein said compound is N-methyl-benzothiazolium-p-toluene sulfonate.

18. The process of claim 16 wherein said compound is decamethylene-bis-benzothjazolium perchlorate.

19. The process of claim 16 wherein said compound is propane 1,3 bis (3-methyl-2-benzothiazolium-p-toluene sulfonate).

20. The process of claim 16 wherein said compound is pentane 1,5 bis (3-methyl-2-benzothiazolium-p-toluene sulfonate).

21. In a process for developing exposed multilayer silver halide photographic elements in a developer having a temperature of at least 100 F., the step of imbibing into the top silver halide layer before development, about 1 to about grams per silver mole in said top silver halide layer of a compound having the following general formula:

wherein R represents a member selected from the class consisting of a hydrogen atom and a lower alkyl group,

R represents a member selected from the class consisting of a hydrogen atom, an aryl group and an arylenethiazolyl group, D represents the non-metallic atoms necessary to complete an aromatic nucleus, X represents an acid radical and n represents a positive integer of from 1 to 26 when R represents a member selected from the class consisting of a hydrogen atom and an arylenethiazolyl group, and n represents a positive integer of from 1 to 3 when R represents an aryl group.

22. The process of claim 21 wherein said compound is N-methyl-benzothiazolium-p-toluene sulfonate.

23. The process of claim 21 wherein said compound is decamethylene-bis-benzothi-azolium perchlorate.

24. The process of claim 21 wherein said compound is propane 1,3 bis-(3-methyl-2-benzothiazolium-p-toluene sulfonate).

25. The process of claim 21 wherein said compound is pentane 1,5 bis-(3-methyl-2-benzothiazolium-p-toluene sulfonate).

References Cited UNITED STATES PATENTS 2,131,038 9/1938 Brooker et al. 96-409 2,288,586 6/1942 Dersch et a1. 96109 X 2,694,716 Ill/1954 Allen et al 96-409 X 3,113,864 12/1963 Yager et a1 96-109 X 3,189,453 6/(1965 Herz et a1 96-61 FOREIGN PATENTS 677,534 l/1964 Canada.

OTHER REFERENCES Crabtree, J. 1.: Rapid Processing of Films and Papers," PSA Journal, vol. 15, February 1949, pp. -136.

NORMAN G. TORCHIN, Primary Examiner.

C. E. DAVIS, Assistant Examiner. 

11. A HARDENING COMPOSITION FOR USE IN AN AQUEOUS PREHARDENER BATH FOR TREATING A PHOTOGRAPHIC ELEMENT HAVING AT LEAST ONE GELATINO-SILVER HALIDE EMULSION LAYER COMPRISING A GELATIN HARDENING AGENT AND A COMPOUND FOR PREVENTING OVERDEVELOPMENT OF THE TOP EMULSION LAYER AND HAVING THE FOLLOWING GERERAL FORMULA: 